U.S. patent application number 10/324906 was filed with the patent office on 2003-06-26 for fuel processor modules integration into common housing.
Invention is credited to Hagan, Mark R., Northrop, William F., Zhao, Jian Lian.
Application Number | 20030118489 10/324906 |
Document ID | / |
Family ID | 23353848 |
Filed Date | 2003-06-26 |
United States Patent
Application |
20030118489 |
Kind Code |
A1 |
Hagan, Mark R. ; et
al. |
June 26, 2003 |
Fuel processor modules integration into common housing
Abstract
A housing containing two or more individual operating components
called modules is disclosed. The modules themselves are
independently contained in one or more vessels with attendant
connectivity structures such as pipes, tubes, wires and the like.
Each such vessel or device is configured to conduct at least one
unit reaction or operation necessary or desired for generating or
purifying a hydrogen enriched product gas formed from a hydrocarbon
feed stock. Any vessel or zone in which such a unit operation is
conducted, and is separately housed with respect at least one other
vessel or zone for conducting a unit operation, is considered a
module. Unit reactions or operations include: chemical reaction;
combusting fuel for heat (burner); partial oxidation of the
hydrocarbon feed stock; desulfurization of, or adsorbing impurities
in, the hydrocarbon feed stock or product stream ("reformate");
steam reforming or autothermal reforming of the hydrocarbon feed
stock or pre-processed ("reformate") product stream; water-gas
shifting of a pre-processed (reformate) stream; selective or
preferential oxidation of pre-processed (reformate) stream; heat
exchange for preheating fuel, air, or water; reactant mixing; steam
generation; water separation from steam, preheating of reactants
such as air, hydrocarbon fuel, and water, and the like.
Inventors: |
Hagan, Mark R.; (Cambridge,
MA) ; Northrop, William F.; (Cambridge, MA) ;
Zhao, Jian Lian; (Boston, MA) |
Correspondence
Address: |
ROBERT W. DIEHL
311 S. WACKER DRIVE
53RD FLOOR
CHICAGO
IL
60606-6622
US
|
Family ID: |
23353848 |
Appl. No.: |
10/324906 |
Filed: |
December 20, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60345170 |
Dec 21, 2001 |
|
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Current U.S.
Class: |
422/600 ;
422/200; 422/204; 422/211; 48/113; 48/119; 48/127.9; 48/197FM;
48/198.6; 48/62R |
Current CPC
Class: |
B01J 2208/00495
20130101; C01B 2203/82 20130101; C01B 3/48 20130101; B01J
2219/00159 20130101; C01B 3/382 20130101; C01B 2203/044 20130101;
B01J 2219/00155 20130101; Y02P 20/129 20151101; C01B 2203/0288
20130101; B01J 2208/0053 20130101; B01J 8/0449 20130101; C01B
2203/0811 20130101; C01B 2203/047 20130101; C01B 2203/1029
20130101; B01J 19/2485 20130101; C01B 2203/0233 20130101; B01J
2219/0002 20130101; B01J 8/0496 20130101; C01B 2203/0244
20130101 |
Class at
Publication: |
422/191 ;
48/198.6; 48/197.0FM; 48/127.9; 48/119; 48/113; 48/62.00R; 422/193;
422/200; 422/204; 422/211 |
International
Class: |
C01B 003/32 |
Claims
We claim:
1. A fuel processor for converting hydrocarbon fuel into hydrogen
gas, the fuel processor comprising: at least two modules, each of
the at least two modules being configured to conduct at least one
distinct unit operation required for reforming hydrocarbons in a
fuel, and the at least two modules being non concentrically aligned
with respect to one another; a housing for housing the at least two
modules together; and, an interstitial space within the housing
juxtapositioned to the individual modules and an inner surface of
the housing, the interstitial space being configured to provide at
least one of the functions selected from the group consisting of
conducting a fluid through the interstitial space for heating the
modules, conducting a fluid through the interstitial space for
cooling the modules, conducting a fluid through the interstitial
space for preheating a fluid, conducting a fluid through the
interstitial space and providing a catalyst therein for reaction,
providing an insulating non-gaseous material in the interstitial
space for insulating the modules, co-housing one or more monolithic
catalyst supports, co-housing one or more granular catalyst
supports, and any combinations thereof.
2. The fuel processor of claim 1 wherein a perimeter bounding the
modules is irregular and wherein the housing has a regular
cross-sectional geometry bounding the at least two modules.
3. The fuel processor of claim 2 wherein the regular
cross-sectional geometry is selected from the group of shapes
consisting of round, circular, obround, oval, elliptical, square,
rectangular, triangular, and regular polygonal.
4. The fuel processor of claim 1 wherein the housing provides
mechanical support for the modules.
5. The fuel processor of claim 1 further comprising an end closure
for the housing wherein the modules are secured by attachment to at
least one end closure.
6. The fuel processor of claim 1 further comprising end closures
wherein at least one end of each module is attached to an end
closure in a way that permits relative movement due to thermal
expansion between or among the modules and the housing.
7. The fuel processor of claim 1 wherein the housing comprises an
integral path for fluid communication between the modules.
8. The fuel processor of claim 7 wherein the integral path for
fluid communication comprises a conduit integrated with an end
closure of the housing.
9. The fuel processor of claim 1 wherein the housing cross section
is defined by a generally regular geometry providing a least
bounding perimeter about the modules.
10. The fuel processor of claim 1 wherein each module conducts unit
reactions selected from the group consisting of combustion of fuel
for heat, partial oxidation of a hydrocarbon fuel, desulfurization
of a feed stock, adsorption of impurities in a reformate or feed
stock, steam reforming of a hydrocarbon feed stock or a
pre-oxidized (reformate) stream, water-gas shifting of a
pre-processed steam reformed or partially oxidized (reformate)
stream, selective or preferential oxidation of pre-processed
(reformate) stream, heat exchange for preheating fuel, air, or
water, reactant mixing, steam generation, and any combination
thereof.
11. The fuel processor of claim 1 wherein the fuel processor is
configured to provide a flow through the interstitial space of a
process fluid for at least one of thermal insulation of the
modules, heat exchange and combinations of same.
12. The fuel processor of claim 1 wherein the interstitial space
contains a material for insulating the modules, the material being
selected from the group consisting of a flowing process fluid, a
solid or semi-solid such as metal or ceramic fibers, a porous
support, a foamed material, or any combination thereof.
13. The fuel processor of claim 1 further comprising at least one
vent to the atmosphere from the interstitial space.
14. The fuel processor of claim 1 further comprising at least one
end closure for the housing, the end closure having at least one
opening interfaced with external plumbing attached to the end
plate.
15. The fuel processor of claims 1 further comprising one end
closure for the housing having an integral manifold for fluid
communication between at least one of the modules and conduit
external to the housing.
16. The fuel processor of claim 1 further comprising: a housing
inlet in communication with the interstitial space; and, a housing
outlet in communication with the interstitial space.
17. The fuel processor of claim 1 wherein the at least two modules
are positioned in close proximity to each other so as to achieve a
compact, efficient utilization of a volume within the housing.
18. The fuel processor of claim 1 further comprising a heat exchang
conduit positioned within the interstitial space for exchanging
heat with fluid flow in the interstitial space.
19. The fuel processor of claim 1 wherein each of the at least two
modules has an elongated dimension and the modules are positioned
so the elongated dimensions of the modules substantially align in
parallel.
20. The fuel processor of claim 1 further comprising a reaction
catalyst disposed in the interstitial space.
21. The fuel processor of claim 1 further comprising an auxiliary
burner incorporated into a first module.
22. The fuel processor of claim 21 wherein the auxiliary burner
comprises an exhaust which heats a thermal conductor disposed about
at least one module.
23. The fuel processor of claim 21 wherein the auxiliary burner
comprises an exhaust which heats a thermal conductor disposed about
the auto-thermal reforming module.
24. The fuel processor of claim 1 further comprising process
conduit in the interstitial space and in operative association with
the modules for conducting their respective unit operations, the
process conduit being selected from the group consisting of heat
exchangers, boiler/steam tubes, electrical conduit, fluid conduit,
or any combination thereof.
25. The fuel processor of claim 1 further comprising an anode gas
combustion burner incorporated into at least one module.
26. A fuel processor for converting hydrocarbon fuel into hydrogen
gas, the fuel processor comprising: at least three modules, each of
the at least three modules being configured to conduct at least one
unit operation required for reforming hydrocarbons in a fuel the at
least three modules being non-concentrically aligned with respect
to one another; and, a housing for housing the at least three
modules together.
27. The fuel processor of claim 26 further comprising an
interstitial space within the housing among the individual modules
and an inner surface of the housing, the interstitial space being
configured to provide at least one of the functions selected from
the group consisting of conducting a fluid through the interstitial
space for heating the modules, conducting a fluid through the
interstitial space for cooling the modules, conducting a fluid
through the interstitial space for preheating a fluid, conducting a
fluid through the interstitial space and providing a catalyst
therein for reaction, providing an insulating non-gaseous material
in the interstitial space for insulating the modules, co-housing
one or more monolithic catalyst supports, co-housing one or more
granular catalyst supports, and any combinations thereof.
28. The fuel processor of claim 26 wherein a perimeter bounding the
modules is irregular and wherein the housing has a regular
cross-sectional geometry bounding the at least three modules.
29. The fuel processor of claim 28 wherein the regular
cross-sectional geometry is selected from the group of shapes
consisting of round, circular, obround, oval, elliptical, square,
rectangular, triangular, and regular polygonal.
30. The fuel processor of claim 26 wherein the housing provides
mechanical support for the modules.
31. The fuel processor of claim 26 further comprising an end
closure for the housing wherein the modules are secured by
attachment to at least one end closure.
32. The fuel processor of claim 30 further comprising an end
closure for the housing wherein the modules are secured by
attachment to at least one end closure.
33. The fuel processor of claim 26 further comprising end closures
wherein at least one end of each module is attached to an end
closure in a way that permits relative movement due to thermal
expansion between and among the modules and the housing.
34. The fuel processor of claim 26 wherein the housing comprises an
integral path for fluid communication between the modules.
35. The fuel processor of claim 34 wherein the integral path for
fluid communication comprises a conduit integrated with an end
closure of the housing.
36. The fuel processor of claim 26 wherein the housing cross
section is defined by a generally regular geometry providing a
least bounding perimeter about the modules.
37. The processor of claim 36 wherein the modules and housing are
arranged such that a module may be removed and replaced separately
from the housing with minimal disruption to other modules.
38. The processor of claim 36 wherein at least one module is
removable from the housing without having to remove another
module.
39. The fuel processor of claim 26 wherein each module conducts
unit reactions selected from the group consisting of combustion of
fuel for heat, partial oxidation of a hydrocarbon fuel,
desulfurization of a feed stock, adsorption of impurities in a
reformate or feed stock, steam reforming of a hydrocarbon feed
stock or a pre-oxidized (reformate) stream, water-gas shifting of a
pre-processed steam reformed or partially oxidized (reformate)
stream, selective or preferential oxidation of pre-processed
(reformate) stream, heat exchange for preheating fuel, air, or
water, reactant mixing, steam generation, and any combination
thereof.
40. The fuel processor of claim 27 wherein the fuel processor is
configured to provide a flow through the interstitial space of a
process fluid for at least one of thermal insulation of the
modules, heat exchange and combinations thereof.
41. The fuel processor of claim 27 wherein the interstitial space
contains a material for insulating the modules, the material being
selected from the group consisting of a flowing process fluid, a
solid or semi-solid such as metal or ceramic fibers, a porous
support, a foamed material, or any combination thereof.
42. The fuel processor of claim 41 further comprising at least one
vent to the atmosphere from the interstitial space.
43. The fuel processor of claim 27 further comprising at least one
vent to the atmosphere from the interstitial space.
44. The fuel processor of claim 27 further comprising at least one
end closure for the housing, the end closure having at least one
opening interfaced with external plumbing attached to an end
plate.
45. The fuel processor of claims 27 further comprising one end
closure for the housing having an integral manifold for fluid
communication between at least one of the modules and conduit
external to the housing.
46. The fuel processor of claims 35 further comprising one end
closure for the housing having an integral manifold for fluid
communication between at least one of the modules and conduit
external to the housing.
47. The fuel processor of claim 27 further comprising: a housing
inlet in communication with the interstitial space; and, a housing
outlet in communication with the interstitial space.
48. The fuel processor of claim 42 further comprising: a housing
inlet in communication with the interstitial space; and, a housing
outlet in communication with the interstitial space.
49. The fuel processor of claim 44 further comprising: a housing
inlet in communication with the interstitial space; and, a housing
outlet in communication with the interstitial space.
50. The fuel processor of claim 45 further comprising: a housing
inlet in communication with the interstitial space; and, a housing
outlet in communication with the interstitial space.
51. The fuel processor of claim 26 wherein the at least two modules
are positioned in close proximity to each other so as to achieve a
compact, efficient utilization of a volume within the housing.
52. The fuel processor of claim 42 further comprising a heat
exchange conduit positioned within the interstitial space for
exchanging heat with fluid flow in the interstitial space.
53. The fuel processor of claim 44 further comprising a heat
exchange conduit positioned within the interstitial space for
exchanging heat with fluid flow in the interstitial space.
54. The fuel processor of claim 45 further comprising a heat
exchange conduit positioned within the interstitial space for
exchanging heat with fluid flow in the interstitial space.
55. The fuel processor of claim 47 further comprising a heat
exchange conduit positioned within the interstitial space for
exchanging heat with fluid flow in the interstitial space.
56. The fuel processor of claim 27 wherein each of the at least
three modules has an elongated dimension and the modules are
positioned so the elongated dimensions of the modules substantially
align in parallel.
57. The fuel processor of claim 27 further comprising a reaction
catalyst disposed in the interstitial space.
58. The fuel processor of claim 40 further comprising a reaction
catalyst disposed in the interstitial space.
59. The fuel processor of claim 41 further comprising a reaction
catalyst disposed in the interstitial space.
60. The fuel processor of claim 26 wherein a first module is
configured to conduct auto-thermal reforming, a second is
configured to conduct a water-gas shift reaction, and a third is
configured to conduct a preferential oxidation reaction.
61. The fuel processor of claim 26 further comprising an auxiliary
burner incorporated into a first module.
62. The fuel processor of claim 61 wherein the auxiliary burner
comprises an exhaust which heats a thermal conductor disposed about
at least one module.
63. The fuel processor of claim 61 wherein the auxiliary burner
comprises an exhaust which heats a thermal conductor disposed about
the auto-thermal reforming module.
64. The fuel processor of claim 27 further comprising process
conduit in the interstitial space and in operative association with
the modules for conducting their respective unit operations, the
process conduit being selected from the group consisting of heat
exchangers, boiler/steam tubes, electrical conduit, fluid conduit,
or any combination thereof.
65. The fuel processor of claim 40 further comprising process
conduit in the interstitial space and in operative association with
the modules for conducting their respective unit operations, the
process conduit being selected from the group consisting of heat
exchangers, boiler/steam tubes, electrical conduit, fluid conduit,
or any combination thereof.
66. The fuel processor of claim 41 further comprising process
conduit in the interstitial space and in operative association with
the modules for conducting their respective unit operations, the
process conduit being selected from the group consisting of heat
exchangers, boiler/steam tubes, electrical conduit, fluid conduit,
or any combination thereof.
67. The fuel processor of claim 57 further comprising process
conduit in the interstitial space and in operative association with
the modules for conducting their respective unit operations, the
process conduit being selected from the group consisting of heat
exchangers, boiler/steam tubes, electrical conduit, fluid conduit,
or any combination thereof.
68. The fuel processor of claim 26 further comprising an anode gas
combustion burner incorporated into at least one module.
69. The fuel processor of claim 61 further comprising an anode gas
combustion burner incorporated into at least one module.
70. A method of reforming hydrocarbon fuels comprising the steps
of: flowing a feed stream in a first direction; generating a
reformate from a first unit operation; flowing the reformate in a
second direction opposite the first; conducting a second unit
operation on the reformate; and, simultaneously exchanging heat in
an interstitial space about a system module via fluid flow there
through among: (a) a heat exchange fluid flowing in either one of
the first or second directions, and, (b) the first and second unit
operations.
71. The method of claim 70 wherein the heat exchange fluid is
reformate generated in the second unit operation.
72. The method of claim 71 further comprising the step of
catalyzing a reaction in the heat exchange fluid simultaneously
with the step of exchanging heat.
73. The method of claim 72 wherein a catalyst used in the step of
catalyzing a reaction promotes preferential oxidation of carbon
monoxide.
74. The method of claim 71 further comprising a catalyst provided
on a porous monolithic support aligned in the direction of flow of
the heat exchange fluid.
75. A method of reforming hydrocarbon fuels comprising the steps
of: conducting at least two distinct unit operations in two
respective individually contained modules which are
non-concentrically aligned and contained within a housing; and,
conducting at least a third unit operation in an interstitial space
defined among the modules and an inner surface of the housing.
76. The method of claim 75 wherein the step of conducting at least
two unit operations in two respective individually contained
modules further comprises the step of selecting the unit operations
from the group consisting of partial oxidation, steam reforming,
water gas shift and any combination thereof.
77. The method of claim 75 wherein the step of conducting at least
one third unit operation in an interstitial space further comprises
the step of selecting the unit operation from the group consisting
of active heat exchange by a flowing heat exchange medium,
preferential oxidation of a reformate generated in the first two
unit operations, preheating of a feed stock including one of fuel,
air, or water, generating steam, and any combination thereof.
78. A method of constructing a fuel processor comprising the steps
of: providing at least two modules configured to conduct at least
one unit operation each; aligning the modules non-concentrically;
housing the modules in a housing; securing each module by its
opposite ends to an end closure of the housing.
79. The method of claim 78 further comprising the step of
configuring an interstitial space defined among the modules and an
inner surface of the housing so that at least one unit operation
can be conducted in the interstitial space.
Description
RELATED APPLICATION
[0001] The present application claims benefit of the priority of
U.S. Provisional Application Ser. No. 60/345,170 filed Dec. 21,
2001.
TECHNICAL FIELD
[0002] The present invention relates generally to fuel processors
for converting hydrocarbon fuels to a hydrogen-enriched gas or
reformate, and in particular, to designs directed to optimizing
integration of one or more unit processes desired in reforming
including integration of several chemical reactors or modules into
a single housing.
BACKGROUND OF THE INVENTION
[0003] Electrochemical devices have long been recognized as having
advantages over more conventional forms of power generation. Due to
the nature of the electrochemical conversion of hydrogen and an
oxidant into electricity, the fuel cell is not subject to certain
Carnot engine limitations, unlike typical prime movers that
generate mechanical work from heat. Though fuel cells can operate
on stored hydrogen, fuel cell systems utilizing fuel processors
have demonstrated similar advantages utilizing hydrocarbon fuels
such as gasoline and methanol, and have certain advantages in terms
of storage capacity, weight, and availability of infrastructure. In
addition, fuel cell systems operating on hydrocarbon fuels also
have a distinct thermal efficiency advantage over traditional
devices. Also, emissions such as carbon dioxide, carbon monoxide,
hydrocarbons, and oxides of nitrogen are relatively low.
[0004] Despite its potential, however, fuel processor technology
has remained largely untapped as a source for hydrogen for fuel
cell systems for a variety of reasons. One significant reason is
the size and complexity of the overall fuel processor and fuel
processor/fuel cell system. In large part, this complexity arises
from the need for many chemical conversion steps in going from the
chemical energy contained in hydrocarbon fuels to the provision of
a hydrogen-enriched gas. For this reason, it has remained very
challenging to package entire fuel cell systems into small spaces;
for example, in vehicle and portable applications
[0005] One obstacle to making fuel processor systems more compact
is the thermal and spatial requirements of the sub-components and
the connectivity between various complementary reaction vessels.
Furthermore, as these complex systems are made to be more compact,
it becomes even more challenging to organize reactors or modules
and thermally integrate each piece of the system while maintaining
an ability to assemble and service it.
[0006] Classical forms of fuel processors are typically large
chemical plants, not subject to severe constraints on weight,
footprint, or thermal efficiency. Therefore there is little
guidance from such conventional technology and there remains a need
for fuel processors that are compact, thermally efficient, and easy
to service.
[0007] EP 1 057 780 A2 A assigned to Toyota, discloses an attempt
to provide integration of multiple unit operations in a single
device (see e.g. FIGS. 39 and 40). The disclosed design provides
for sequential process or reaction modules in a reforming process
and fuel conditioning process. Reactor or module sections 30 and 62
are connected via a clamped connection. A pipe 66 joins modules 62
to 64 and redirects reformate flow 180 degrees. Reactor module
sections 64 and 80 are also connected by a clamp connection. The
assembled fuel processor of this Toyota design is difficult to
mount under the floor of a vehicle without allowing mechanical
strain to be applied to at least some of these joints, including
the clamped connections. Housing 61 provides an insulating function
but does not appear to stabilize any of the above-discussed
connections in any significant way, in particular the connections
between modules 30-62, 62-64, and 64-80, respectively.
[0008] It is also noted that housing 61 is double walled and
insulating is carried out by a space defined between the walls of
the housing 61. Accordingly, there is a significant space
utilization inefficiency in that unused interstitial space remains
between the modules 62, 64 and the housing 61.
[0009] Other approaches having significant degrees of success at
providing a fuel processor with optimized thermal and mechanical
integration of unit processes are those concentrically arranged,
e.g. nested cylinders as disclosed in U.S. Pat. Nos. 6,254,839 and
6,245,303; and WO 00/66487, all assigned to the assignee of this
application. However, in certain applications, such as in on-board
transportation applications, physical shape and orientation of an
integrated reactor can be restricted by the particular design
considerations for a particular vehicle. Accordingly, for any given
reactor output desired, a concentric design may provide a reactor
diameter to reactor length ratio which is not as favorable as a
non-concentric design. This consideration may become more
pronounced as the degree of integration within a single reactor
housing increases towards providing all of the unit operations
desired or necessary to provide acceptable quantity and quality of
hydrogen for the application.
[0010] The present invention meets the above deficiencies in the
art, as well as providing a variety of other benefits and
advantages associated with the construction and use of integrated
fuel processors.
SUMMARY OF THE INVENTION
[0011] According to one aspect of the present invention, a housing
contains two or more individual devices. The devices themselves are
independently contained in one or more vessels with attendant
connectivity structures such as pipes, tubes, wires and the like.
Each such vessel or device is configured to conduct at least one
unit reaction or operation necessary or desired for generating or
purifying a hydrogen enriched product gas formed from a hydrocarbon
feed stock.
[0012] For the purposes of the invention, any vessel or zone in
which such a unit operation is conducted, and is separately housed
with respect at least one other vessel or zone for conducting a
unit operation, shall be referred to as a module.
[0013] Unit reactions or operations include: chemical reaction;
combusting fuel for heat (burner); partial oxidation of the
hydrocarbon feed stock; desulfurization of, or adsorbing impurities
in, the hydrocarbon feed stock or product stream ("reformate");
steam reforming or autothermal reforming of the hydrocarbon feed
stock or pre-processed ("reformate") product stream; water-gas
shifting of a pre-processed (reformate) stream; selective or
preferential oxidation of pre-processed (reformate) stream; heat
exchange for preheating fuel, air, or water; reactant mixing; steam
generation; water separation from steam, preheating of reactants
such as air, hydrocarbon fuel, and water, and the like.
[0014] According to another aspect of the invention, such modules
and their attendant connectivity structures present somewhat
irregular perimeter geometries and/or present somewhat asymmetric
assemblies, while the housing presents a more regular and/or
symmetrical cross section and/or perimeter.
[0015] According to another aspect of the invention, the
interstitial space among the modules, their attendant connectivity,
and the inner surface of the housing, is configured to serve a
useful function. Among these useful functions are: (a) providing
either a fluid or a solid substance in the interstitial space to
insulate the reactors or modules components and/or their
connectivity, or to assist in thermal equilibrium among same; (b)
flowing fluid through the interstitial space for heat exchange to
accomplish heating or cooling of the module or both; (c) providing
a flow of fluid through the interstitial space for heat exchange to
accomplish heating of the fluid for further use in the system, such
as preheating a reactant feed stream; and, (d) providing a granular
or monolithic catalyst in the interstitial space and providing a
flow of fluid through the interstitial space for reaction on the
catalyst.
[0016] According to another aspect of the invention, the housing
provides improved mechanical support for the modules.
[0017] According to another aspect of the invention, the housing
itself, in particular its end closures provide interconnection of
fluid flows among the reactors or modules.
[0018] According to another aspect of the invention, either the
housing, or the internal modules and their connectivity, or both,
are arranged so that at least one portion of the interstitial space
can be fitted with one or more unitary bodies providing for any one
of insulation, catalysis, heat exchange or any combination of the
above. Preferably these bodies can be made with regular geometries.
The bodies may be porous, elongate or cooperatively stacked
segments, or combinations of these.
[0019] According to another aspect of the invention, the housing is
sized and shaped to provide a least bounding generally regular
geometry to bound the modules and their connectivity.
[0020] Prior art designs for fuel processors typically stop at the
level of integration of unit functions into a module. The modules
are then placed wherever convenient and interconnected as required.
We have found instead that when the system is best constructed as
comprising more than one module, it is efficient to assemble the
modules in a common housing so as to provide a physically
integrated unit. The initial motivation for this assembly in a
housing was to maintain the units in a fixed relationship to each
other, and in some cases to minimize system heat losses. However,
we have found that the process of integrating modules in a housing
provides many additional unexpected benefits, particularly in the
areas of manufacture, ease of repair, and service. The systematic
use of design and assembly principles produces an integrated fuel
processor that is both highly efficient and easy to assemble and
maintain.
[0021] The following are examples of benefits provided by the
integrated fuel processor of the invention: more flexibility in
selecting the physical shapes of units; e.g., monolithic catalyst
supports; better serviceability while retaining a very compact fuel
processor. Reactors or modules can be changed out very quickly and
replaced as opposed to having to dismantle an entire fuel processor
assembly; utilization of the interstitial space as a conduit for
flowing a heat exchange medium, including a process gas, for
thermal integration of the modules. Alternatively, the interstitial
space can be void of any process fluid and may contain insulating
materials such as a ceramic fiber blanket. In the first instance,
the housing could be a pressurized vessel; in the second instance,
the housing would not need to withstand internal pressure and may
be vented to the atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The present invention can be more readily understood with
reference to the accompanying drawings, in which like numerals are
employed to designate like components throughout the disclosure,
and where:
[0023] FIG. 1 is a first perspective, partially exploded view of a
fuel processor in accordance with the present invention having two
main modules;
[0024] FIG. 2 is a cross sectional assembled view taken along line
2-2 of the embodiment of the fuel processor shown in FIG. 1;
[0025] FIG. 3 is a schematic cross sectional side view taken along
line 3-3 of the embodiment of the fuel processor shown in FIG.
1;
[0026] FIG. 4 is a second perspective view of the embodiment of the
fuel processor shown in FIG. 1 without the common housing and
illustrating one embodiment of module attachment to end
closures;
[0027] FIG. 5 is a schematic of another embodiment of a fuel
processor in accordance with the present invention having three
main modules;
[0028] FIG. 5A is a cross sectional view taken along line 5A-5A of
the embodiment of the fuel processor shown in FIG. 5;
[0029] FIG. 6 is a drawing (FIG. 39) from EP 1 057 780 A2
disclosing a fuel processor; and
[0030] FIG. 7 is a drawing (FIG. 40) from EP 1 057 780 A2
disclosing a fuel processor.
DETAILED DESCRIPTION OF THE INVENTION
[0031] While this invention is susceptible of embodiment in many
different forms, preferred embodiments of the invention will be
described below in detail with the understanding that the present
disclosure is to be considered as an exemplification of the
principles of the invention and is not intended to limit the broad
aspect of the invention to the embodiments disclosed. It should
also be understood that not every disclosed or contemplated
embodiment of the invention needs to utilize all of the various
principles disclosed herein to achieve benefits according to the
invention.
[0032] FIGS. 1-4 disclose a fuel processor 10 for converting
hydrocarbon fuel into a hydrogen-enriched gas or reformate. The
fuel processor 10 includes two modules 12a and 12b, each of which
is self-contained and configured to conduct a unit operation
required for reforming hydrocarbons in the hydrocarbon fuel feed
stock. As necessary or desired the fuel processor 10 sufficiently
purifies the resulting syn-gas or reformate for its ultimate use,
such as integration with a fuel cell (not shown).
[0033] Unit Operation And Orientation Of Modules
[0034] A housing 14 houses two modules, first module 12a and second
module 12b. Each module 12a, 12b is configured to conduct at least
one unit reaction/operation required toward a desired yield of
hydrogen. The unit reactions contemplated for the example of fuel
processor 10 may be carried out by, in a preferred operational
order, a burner, a reformer (selected from a partial oxidation
(POx) reactor, a steam reformer, or a combination autothermal
reformer), a shift reactor (both high temperature and low
temperature shift), and a preferential oxidation (PrOx) reactor.
All of these unit reactions need not be present or identically
arranged with their respective reactor components for all uses. For
example, the module 12a may include a partial oxidation reaction in
section 20 thermally coupled with a steam reforming reaction of the
hydrocarbon feed stock (the combination thereof providing
autothermal reforming or "ATR") in section 22, to generate a
reformate. Both a high temperature water-gas shift (HTS) and a low
temperature water-gas shift (LTS) reaction may be carried out in
two succeeding sections 16 and 18 of module 12b.
[0035] Modules 12a, 12b, are aligned in parallel and together
present a somewhat irregular and interrupted perimeter geometry.
The obround housing 14 on the other hand, presents a more regular
and/or symmetrical cross section and/or perimeter. The housing 14
is sized and shaped to provide a least bounding generally regular
geometry (obround in this case) to bound the side-by-side
cylindrical modules 12a and 12b, according to one aspect of the
invention.
[0036] In other embodiments, as with housing 14, the housing shape
is also selected based on its ease of manufacture and the ability
to fit the space allocated to the particular fuel processor.
Another consideration is whether the housing is to be pressurized.
Generally, the housing is sized to provide efficient packaging and
serviceability of the modules and associated connections.
[0037] For example, FIG. 5 discloses a fuel processor 11 having
three (3) main cylindrical modules 34, 36, and 38 each for
conducting distinct unit operations. A least bounding geometry, or
right circular cylindrical housing 40, houses the reactors or
modules 34, 36, 38. It should be understood that other geometries,
for example a triangular cylinder could provide a least bounding
regular geometry for housing the three modules 34-38.
[0038] The unit processes contemplated by way of example in fuel
processor 11 are; ATR in module 38; HTS and LTS successively in
module 36; and preferential oxidation in one or more stages or
thermal gradients in module 34.
[0039] Interstitial Space
[0040] FIGS. 1-3 disclose an interstitial space 24 defined among
the modules 12a and 12b and an inner surface 26 of the housing in
fuel processor 10. FIG. 4 discloses an interstitial space 42
defined among the modules 34-36 and an inner surface 44 of a
housing 40.
[0041] FIG. 1 discloses that a significant portion of the
interstitial space 24 of fuel processor 10 is advantageously
occupied by insert modules 28. The inserts 28 conduct a unit
operation but advantageously are designed to fit the interstitial
space left by housing two cylinders by an obround housing. In other
words, the interstitial space 24 defines the vessel in which this
unit operation occurs. In one embodiment the inserts 28 are
preferably a foam structure which can also provide insulation of
the modules 12a and 12b and heat exchange with the modules 12a and
12b. In another embodiment, a heat exchanger such as that disclosed
in U.S. Ser. No. 60/304,987 may be configured to fit into
irregularly shaped interstitial spaces.
[0042] FIG. 2 discloses a preferred use of the inserts 28 and the
interstitial space 24. In the disclosed embodiment, the foam
inserts support one or more catalysts suitable for promoting
preferential oxidation of CO in the reformate stream generated by
modules 12a and 12b.
[0043] It is contemplated that in other embodiments fuel processors
such as 10 or 11 having corresponding interstitial spaces such as
24 or 42 could: (a) permit routing of individual conduits
configured to exchange heat with a fluid in the interstitial space
and/or the modules, or both, such as for preheating a feed stock in
the conduit; (b) be configured as in fuel processor 10 to itself
substantially define a conduit for a fluid flow fluid for heat
exchange with the modules including heat exchange modules; (c)
house one or more solid substances to insulate all or part of the
modules and/or their connectivity; or (d) house a granular catalyst
or absorbents or adsorbents pretreatment of feed stock or a
post-treatment of reformate. Of course, interstitial space 42 of
fuel processor 11 could be configured to contain foam inserts, such
as inserts 28 and function in a similar manner, albeit the inserts
having a slightly different shape.
[0044] Mechanical Connection
[0045] FIGS. 1-4 disclose the unique structural integrity,
modularity, and fluid connectivity provided by utilization of the
principles of the invention. FIG. 4 in particular, discloses the
fuel processor 10 without its housing 14. In this view is can be
seen that the modules 12a, 12b are fixed by end closures 30,32 in
secure alignment with each other, and with respect to the perimeter
where housing 14 will reside. Because the modules 12a, 12b are
secured, the inserts 28 are easily stabilized by having a shape
that inter fits within an interstitial space between the modules
12a, 12b and the housing inner surface 26.
[0046] Fuel processor 11 (FIG. 5) is constructed in a similar
manner, whereby the modules 34-38 are secured in proper alignment
by connection to end closures 46 and 48.
[0047] In other embodiments, it is contemplated that added support
for the modules could be provided by spacers placed between the
modules or the inner surfaces of the housings 14 and 40 of the fuel
processors 10 and 11. Such spacers may be in the form of discrete
mechanical shims, brackets or the like, or could be comprised of
sheets of metal foam, mesh, expanded metal, dimpled metal or screen
so as not to displace fluid or restrict fluid flow.
[0048] In other embodiments it is contemplated that mechanical
stability will be increased if the modules are cross-braced or
otherwise supported against each other. It may also be convenient
to shape the housing so that when it is fitted down over the
modules, contacts or attachments between the modules and the inside
of the housing increase the mechanical stability of the modules
with respect to each other and to the cover.
[0049] In general, according to the invention, when modules are
secured to end caps/closures and are provided with internal spacing
support when required, then the integrated fuel processor does not
place any strain on the seals connecting the modules.
[0050] Fluid Communication Between Modules
[0051] FIGS. 1, 3, 4 and 5, disclose the advantageous
interconnection of fluid flows among the modules 12a ,12b, and the
interstitial space 24 as disclosed in FIGS. 1-3 and provided by the
invention.
[0052] In fuel processor 10, a raised cross-over manifold 50
integral with end closure 30 interconnects one end of each of
modules 12a and 12b for flow of reformate as shown in FIG. 2.
Likewise, an embedded channel-type cross over manifold 52 is
integral with end closure 32 for providing fluid communication
between module 12a and the interstitial space 24, in the manner
disclosed in FIG. 2. While these fluid manifolds are disclosed as
relatively integral with end closures 30, 32 it is contemplated
that any suitable pipe, conduit or the like may be suitably
attached to, or otherwise integrated into an end closure to receive
benefits according to the invention.
[0053] An outlet pipe 54 is provided on end closure 30 for exiting
hydrogen enriched product gas and for connection with appropriate
external routing to an end use, such as a fuel cell. Inlet port 56
is provided on end closure 32 for supplying fuel, fuel and steam,
fuel and water, and oxygen, or any combination thereof as desired
for carrying out the reforming process desired in module 12b.
[0054] FIG. 4 discloses that the modules 12a, 12b are connected to
end closure 32 by bellows connectors 58 and 60. These connectors
advantageously provide stable alignment of the modules while
permitting relative longitudinal expansion and contraction of the
modules versus the housing 14 during thermal excursions of the fuel
processor 10.
[0055] FIG. 5 discloses fluid connectivity into, out of, and within
the fuel processor 11 in a like manner to that of fuel processor
10. This is accomplished through manifolds 62 and 66 on end
closures 46,48 respectively and inlet 68 and outlet 64 on end
closures 48, 46 respectively.
[0056] In general a further advantage of the combination of the
housing and the mani-foldbearing end closures is that assembly is
markedly simplified. A significant fraction of the required
"plumbing" (interconnections among fluid flows) can be built into
the manifolds (and into the modules), so that many fewer individual
connections will be required to assemble a fuel processor.
[0057] To that end, passages may be provided in the end units, or
other portions of the processor, in any known way. These includes
machining, forming, stamping, drilling, or welding or brazing of
other structures onto the end caps, and combinations of these. The
passages will be provided with fittings into or onto which the
modules may be affixed. Means of fixation of modules on the end
fittings or the manifolds attached to them can also be any known in
the art, with due regard for the nature, pressure and temperature
of the fluids to be passed through the manifold.
[0058] Modularity
[0059] As can clearly be seen in view of the above disclosures, the
modules 12a,12b of fuel processor 10 and 34-38 of fuel processor
11, can be easily assembled and replaced by removal of either one
or both of the end closures (30, 32 or 46, 48) of the respective
housings 14 and 40. This is due in one respect to the convenient
arrangement of the physical vessels comprising the modules. It is
also due in another respect by the convenient grouping of unit
functions into a particular module. For example, certain catalysts
may be poisoned more readily by certain contaminants than others,
certain catalysts may have a shorter operational life than others,
etc. Thus, in the present designs, catalysts for HTS can be removed
without removal of the ATR module or its catalyst section and vice
versa. Likewise, the choice of which catalysts to put together in a
module can be optimized according to expected needs for changing
during operation.
[0060] This also highlights the linear concentric modularity of
module sections, such as sections 16 and 18 (HTS and LTS,
respectively) and 20,22 (partial oxidation and steam reforming).
The modules 12a,12b can in a desired embodiment separate into
sections and hence even a section of a module may be easily
assembled or removed and replaced by simple removal of the end
closures.
[0061] In general, according to the invention, for efficiency,
several functional units may be integrated into a single module,
but it is not always practical, or even desirable, to integrate the
entire system into a single module. Considerations affecting the
degree of modularity include ease of assembly and repair,
replacement of consumables, thermal compatibility, and system
efficiency.
[0062] All modules can contain one or more of catalysts, catalytic
reaction zones, adsorbents, heat exchangers, mixers, or other
units. These are fully contained within a given module or sections
thereof. However, according to the invention, the interstitial
space not taken up by a self-contained module, may contain these
individual items or assist in these functions as desired for a
particular design. Leak-tight modules such as heat exchangers that
can assume odd shapes to fill voids can be also used.
[0063] Heat Exchange Configurations
[0064] As disclosed with respect to fuel processors 10 and 11, in
modular configurations, individual modules may contain more than
one unit function integrated into the module. For example, it is
usually expedient (although not required in the invention) to
integrate the heat-absorbing steam reforming reaction into a module
so as to provide direct contact with available heat emitting
reactions, particularly partial oxidation units, auxiliary heat
burners, exothermic reactions, autothermal reactions, burners
and/or high temperature water gas shift units; and to combine these
with integrated heat exchange means. On the other hand, lower
temperature reactions may expediently be placed in separate
modules, or in a common second module.
[0065] Heat exchanger modules typically transfer heat from hot
components, such as the exhaust of a catalytic burner and the
reformate, to components requiring preheating, such as water
requiring conversion to steam, or fuel requiring vaporization.
[0066] Additionally, modularization increases the efficiency of
heating elements that are disposed between the inner surface of a
thermally insulated module wall and an element requiring heating,
such as a steam reformer. A heater such as a burner, when employed
as an ignition source, will operate much more efficiently,
particularly if its exhaust can be used as a needed auxiliary heat
source or thermal insulator. After running the fuel processor for a
short while, the burner's ignition source can often be extinguished
when the burner material attains a sufficiently high temperature to
ignite incoming reactants. Accordingly, in other embodiments of the
invention a fuel processor comprising a partial oxidation module or
and ATR module, can include a burner the exhaust of which can be
flowed in the interstitial space to heat a thermal conductor which
is disposed about the module, and, optionally, contacts by direct
convection the module.
[0067] In other embodiments, anode waste gas from a fuel cell can
be fed to a module to assist reforming, or it can be fed to a
burner incorporated into a module, or it can be directed through an
interstitial space between modules for heat exchange, or a
combination of these.
[0068] Method
[0069] As best disclosed in FIG. 2, a method of reforming
hydrocarbon fuels in fuel processor 10 according to the invention
includes conducting a first unit operation on a reaction stream
flowing in a first direction in module 12b, and generating a
reformate from a first unit operation, ATR. At the same time,
reformate is flowed in a second direction through module 12a while
conducting a second unit operation water-gas-shift. The flow
direction through these modules 12a,12b is in opposite
directions.
[0070] Residence time of reactants in a reactor section (module or
sub-component of a module) e.g. in the flow through a catalyst bed,
(such as is the case with catalytic partial oxidation, steam
reforming, autothermal reforming, water-gas-shift, and preferential
oxidation), is a significant factor in efficacy and efficiency of a
fuel processor. The length of a such reaction zone or reactor is a
significant factor in determining residence time. (Other factors
influencing residence time, or its inverse, space velocity, include
pressure, bed cross sectional area, and pore volume of the catalyst
bed. Advantageously according to the invention, the total residence
time of reactants flowing through all of the unit operations of
fuel processor 10 can be twice as long as a fuel processor of
equivalent overall length, i.e. from end closure to end closure.
Put another way, if modules 12a and 12b were not packaged side by
side but in a linear succession, the fuel processor 10 would have
to be approximately twice as long. For some applications, such a
configuration would be unsuitable. The structural integrity too, of
such a linearly aligned processor would be likely compromised by
comparison.
[0071] The above advantage is multiplied in fuel processor 10 by
use of the interstitial space 24 as a vessel for conducting the
unit operation of preferential oxidation. This use of common
housing 14 for non-concentric reaction zones reduces overall length
of fuel processor 10 by approximately a factor of three (3) with
respect to the modules contemplated in fuel processor 10.
[0072] It is also contemplated that further method or process
advantages will be achieved by providing a common housing for at
least two non-concentrically aligned modules wherein the
interstitial space is used as a vessel for simultaneously
exchanging heat among, a heat exchange fluid flowing in either one
of the first or second directions in connection with both the first
and second unit operations. In particular a process advantage is
achieved where the heat exchange fluid is reformate generated in
the second unit operation, and more particularly when catalyzing a
reaction in the heat exchange fluid by flowing the fluid through a
catalyst while simultaneously exchanging heat. In particular, such
a process is disclosed in fuel processor 10 as conducting
preferential oxidation on porous monolithic supports 28 aligned in
the direction of flow of the heat exchange fluid.
[0073] Method Of Constructing A Fuel Processor
[0074] As disclosed in FIGS. 1-5, the present invention provides
advantages in the manufacture and maintenance of a fuel processor.
Specifically processes for making a fuel processor include
providing at least two modules configured to conduct at least one
distinct unit operation each and aligning the modules
non-concentrically. The process also includes housing the modules
in a common housing and securing each module proximate its opposite
ends to, or proximate to, an end closure of the housing.
[0075] As also disclosed in FIGS. 1-5, another aspect of a process
according to the invention is configuring the fuel processor so
that an interstitial space among the modules and the housing can be
used as a vessel or conduit for useful work, such as for performing
a unit operation therein without the need for further
modularization or the provision of further vessels.
[0076] Although this specification discloses, illustrates, and
describes specific embodiments, numerous modifications come to mind
without significantly departing from the spirit of the invention.
The scope of the protection is limited only by the scope of the
accompanying claims.
* * * * *